Sentence - Future Perfect vs Future Simple

[Raf]

Hello everybody,
I have this sentence from an English test:

According to the last forecast, the tunnel
a) will be finished next year.
b) will have been finished next year.

The book says that A is correct - okay, it sounds fine - but I don't see what's wrong with B. After all we use Future Perfect to say that something will have been completed in the future. So why is B not correct?

Thanks in advance!

[Alan]

Hi Raf,

Both 'will be finished' and 'will have been finished' have different meanings. (a) makes better sense because here you are saying that the tunnel will be ready for use. (b) needs a link between then and now as: will have been finished by this time next year.

Alan
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English as a Second Language
You can read my ESL story Present Simple